The Journey of a Kidney Stone – Or How We Pass Them

When most people pass a kidney stone, all they know is that it generally involves an intense amount of pain and is typically accompanied by a few other symptoms, such as nausea or blood in the urine. However, have you ever wondered exactly how a kidney stone develops and then leaves your body? To best understand this journey, you must first know a little bit about the human body.

To get started, it’s important to note the body contains two kidneys, which are located in the upper abdomen in the area of your ribcage. These organs, which are indeed shaped like kidney beans, are responsible for clearing excess waste from our blood and preparing it to leave our body in the form of urine.

Once the urine leaves the kidney, it travels down through a cavity called the renal pelvis and into the ureter, which is the tube connecting the kidney to the bladder. From there, the urine enters the bladder, where it sits until the bladder is full and you go to the bathroom. This part of the process effectively eliminates the urine from your body through another tube, which is smaller in length and called the urethra.

This is the same path that a kidney stone follows when attempting to pass. The stone starts in the kidney, works its way down through the renal pelvis and into the ureter before entering the bladder, where it’s held until it is expelled through the urethra. When the stone is in the bladder, The Urology Group noted that “the hard work is done” because the ureter is about four times smaller than the urethra, making the second part of the trip easier and usually relatively pain-free.

However, sometimes the journey isn’t quite so smooth. The stone can get stuck and block the renal pelvis or the ureter. If this occurs, urine can be prevented from moving from the kidney to the bladder. This is where the pain comes in, because there is increased pressure on the kidney. And if the block is just intermittent, due to the stone moving, the pain also becomes intermittent.

In most cases, the stone will eventually pass on its own. If it doesn’t, it remains lodged, or is too large for your body to expel, medical intervention can be necessary to complete the passing process.